v0.2.0

Minor release since v0.1.0:

- CI now builds and tests the embed-web feature on every build, and
  make-release.sh smoke-checks the built binary before packaging
  (docs/DECISIONS.md #76).
- Content-hashed _astro/* assets get an immutable Cache-Control in both
  serving modes (docs/DECISIONS.md #77).
- Decided against stripping the release binary (docs/DECISIONS.md #78).

Triggers Jenkinsfile's Release stage to build and archive the
single-binary x86_64-unknown-linux-musl release tarball.